Secure optical information disc

ABSTRACT

A secure optical data disc comprising an electronic article surveillance tag embedded within a layered disc structure comprising first and second substrates is disclosed. The tag is placed within a non-readable zone (i.e., one that does not have data tracks) of the secure disc. Layer-wise, the tag is either sandwiched between the two substrates or alternatively embedded within one of the two substrates. In the case where the tag is sandwiched between first and second substrates, a bonding layer occupies a space radially outward from the tag.. The bonding layer holds the first and second substrates together thereby forming the secure disc.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Bigley, U.S. ProvisionalPatent Application Ser. No. 60/455,284, filed on Mar. 17, 2003, andBigley, U.S. patent application Ser. No. 10/792,352, filed on Mar. 3,2004, (now U. S. Pat. No. 6,947,371, issued Sep. 20, 2005) entitled“Secure Optical Information Disc,” the contents of both referencedpatent applications are incorporated herein by reference in theirentirety, including any references therein.

TECHNICAL FIELD

This invention generally relates to electronic data storage media suchas those used to store music, movies, software (including games), andother valuable electronic data assets distributed through retail and/orrental outlets. More particularly, the invention relates to themanufacture of optical data storage discs for carrying an electronicallydetectable security tag. The security tag potentially embodies a varietyof electronic article surveillance (EAS) technologies including onesthat generate specific identification codes for inventory control (e.g.,RFID and smart tags) as well as ones that, unless deactivated, resonateat a particular frequency (or range) and activate an alarm when passedthrough an electronic surveillance gate.

BACKGROUND

Optical data storage discs are the predominant media for storing music,movies and software (including general PC software as well video gamesoftware played upon game consoles connected to televisions/monitors)distributed via retail outlets. Today, music is encoded on an opticaldata storage disc using compact disc (CD) technology. Software that isdistributed through retail outlets is also typically stored on opticaldata storage discs embodying the CD technology. Movies and games(executed on game consoles) are encoded on optical data storage discsusing digital versatile disc (DVD) technology that holds significantlymore data than a CD.

Retail theft of optical data storage discs storing valuable digital dataassets has received considerable attention from retailers. Initially,theft was deterred through the use of bulky, six by 12 inch cardboardboxes that were difficult for shoplifters to conceal. Later, equallybulky, plastic frames were placed around the boxes to deter theft. Whilesuch packaging was an effective deterrent, it created substantial solidwaste. Thus, the bulky boxes were abandoned and today, CDs are generallypackaged in the well-known “jewel” case. Similarly, DVDs for movies aregenerally displayed for retail customers within slightly larger plasticcases including one or more optical data storage discs. On the otherhand, retailers have resorted to placing DVDs containing game consolesoftware in locked cabinets to deter theft.

In the 1990s electronic security mechanisms replaced bulky packaging asa means for discouraging/controlling retail theft. In particular,electronic surveillance tags are now placed on/within optical discstorage retail packaging. Unless deactivated at the checkout counter,the security tags are sensed by surveillance panels positioned at theentrance/exit of a retail establishment. If not deactivated, sensorswithin the panels detect the security tag when a person attempts toleave with the case containing the security tag and an alarm isactivated. A number of such security tag technologies are well known inthe art.

Currently electronic security tags are attached to a case within which aDVD, for a movie or game, is held. If the case is taken from a retailestablishment before the security tag is deactivated, then an alarmsounds when the security tag passes through security panels at the door.A shortcoming of attaching security tags to a package/case containing anoptical disc is that a shoplifter need only remove the disc from thepackage (or remove the security tag from the package) to evade detectionby security panels placed at a store's exit. As a consequence, retailerscontinue to maintain their game software within locked cases.

Alternatively, and apparently to address the shortcomings of attaching asecurity tag to a CD case, attaching a security tag to a CD disc havinga single substrate has been proposed a number of times in the prior art.These previous proposed CD structures have yet to be adoptedcommercially by retailers. Introducing a security tag introduces thepossibility that the security tag will interfere with playing the discby a purchaser of the disc. One problem arising from attaching asecurity device directly to a disc is the need to maintain balance.Another restriction is that incorporating a security tag onto the discitself should not cause the disc to no longer meet specifiedspace/dimension standards for the particular optical data storage media.

SUMMARY OF THE INVENTION

The present invention is directed to a secure disc arrangement andmethod for manufacturing the secure disc such that a resulting opticaldisc is produced in a manner conforming to the space limitations of theoptical disc media standards organizations as well as meeting theproduction throughput timing requirements of manufacturers—therebyproviding both a technological as well as commercially acceptablesolution to a need to control theft of movies, programs and games storedupon optically encoded media (e.g., DVDs) comprising two substrates thatare produced/provided via two distinct production lines.

The present invention thus comprises a secure optical data storage disc.The secure disc includes a first substrate that is separate and distinctfrom a second substrate. The substrates, by way of example, are formedby injecting molten plastic within a mold. The secure disc has anon-readable zone that does not include data tracks (disposed upon areadable surface of the disc). A security tag is disposed within thenon-readable zone of the disc and thus does not interfere with readingthe data tracks. The format and layering of the data tracks differs inaccordance with various embodiments of the invention.

The present invention also comprises a method for manufacturing a secureoptical data storage disc that includes a first substrate, a secondsubstrate, and a non-readable zone that is not occupied by data tracks.The method comprises initially forming the first substrate and thesecond substrate in any of a variety of ways. In embodiments of theinvention, a pattern is embossed upon at least one of the substrates.The embossed substrate is thereafter covered by a thin reflective layer(or semi-transmissive layer in the case of an outer layer of a dualreadable-layer side). In accordance with the present invention asecurity tag is secured to one of the first or second substrates withinthe non-readable zone. In an embodiment of the invention, the tag isplaced upon one of the substrates prior to bonding the two halvestogether. However, in an alternative embodiment the tag is-embeddedwithin one of the two substrates during an injection molding stage thatproduces the substrate. The secure disc, with its encased security tag,is formed by bonding the first substrate and second substrate togethersuch that the security tag is positioned between the first and secondsubstrates.

The present invention is intended to encompass a variety of opticallyencoded discs carrying a variety of information assets within areflective/semi-transmissive layer carried between two substrates. Theinvention is embodied, for example, within DVDs that are encoded withmovies, videogame console game software, and software in general. Suchembedding prevents separation of a disc from its EAS tag and as suchprovides a significantly higher barrier to circumvention by would beshoplifters than other known arrangements that merely embed the tagwithin a case. The present invention is intended to be carried outthrough the use of a variety of thin film EAS technologies arranged in avariety of topologies and circuits. The invention will be described, byway of illustrative examples, further herein below.

BRIEF DESCRIPTION OF THE DRAWINGS

While the appended claims set forth the features of the presentinvention with particularity, the invention, together with its objectsand advantages, may be best understood from the following detaileddescription taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a schematic plan view of an exemplary secure disc comprisingan annular security tag sandwiched between two substrates of an opticaldisc and located within the non-data region of disc;

FIGS. 2 a–2 c are cross-sectional views of various types of secure DVDdisc formats;

FIGS. 3 a–d are a set of plan views of various security tag coilconfigurations;

FIGS. 4 a–4 b are DVD layer summaries for an initial molding stage forDVD-14 and DVD-18 formats;

FIGS. 5 a–5 b are DVD layer summaries for an intermediate (stripped)stage for DVD-14- and DVD-18 formats;

FIGS. 6 a–6 b are DVD layer summaries for a final assembly stage forDVD-14 and DVD-18 formats;

FIG. 7 is a plan view of an assembly line for carrying out DVDmanufacturing in accordance with an embodiment of the present invention;and

FIGS. 8 a–8 b summarizes exemplary fabrication stages for DVD-5 andDVD-9 discs comprising security tags embedded between two substrates.

DETAILED DESCRIPTION OF THE DRAWINGS

A secure disc, including all formats (e.g., CD, DVD, etc.), comprises asecurity tag sandwiched between first and second substrates of thesecure disc. At least an antenna portion of the security tag occupies aregion of the disc that is not encoded with optically sensed data. Thelocation of the security tag avoids interfering with optically senseddata stored upon the secure disc. In exemplary embodiments, the securitytag is sandwiched between first and second substrates at a location nearthe hub of the secure disc (e.g., within a clamping region, andpotentially extending into a mirror band area).

Furthermore, the security tag is substantially balanced with regard to arotational axis of the secure disc. In an embodiment of the inventionthe security tag is ring-shaped (i.e., defined by concentric circularinner and outer edges). Thus, when concentrically embedded/sandwichedbetween two substrates of the secure disc, the thin film security tagneither unbalances the disc nor interferes with data acquisition fromthe disc.

The present invention contemplates a variety of thin film EAS sensortechnologies/topologies. In particular embodiments of the invention, thesecurity tag is provided in the form of an insulated thin filmresonating device including capacitively coupled coiled circuits,carried by an insulating thin film, constituting an inductor/capacitor(LC), or resonant, circuit. The insulating thin film establishes thecapacitive aspect of the LC circuit by slightly offsetting pairs ofmetallic coils that make up the security tag. The paired coils of thesecurity tag have sufficient surface area to resonate when exposed toelectromagnetic energy at a frequency within a particular frequencyrange. Alternatively, a separate capacitor circuit, separate from themetallic coils, provides at least a portion of the capacitive aspect ofthe security tag. The signal generated by the security tag sandwichedbetween the two substrates of an optical data storage disc is detectedby a receiving antenna thereby making it a viable electronic articlesurveillance anti-theft device capable of discouraging theft of theoptical data storage disc.

Turning to the drawings, and in particular FIG. 1, the invention ispresented in the form of a secure optical data storage disc 100 (alsoreferred to herein as “secure disc 100”) that comprises a security tag102 sandwiched/embedded between a first and second substrate. Ingeneral, the tag occupies a non-readable surface area on the disc 100.In the illustrative embodiment, based upon DVD standard dimensions, thesecurity tag 102 comprises a thin film LC resonating device thatresides, by way of example, primarily within an annular clamping area106 of the secure disc 100 (and centered with regard to the axis ofrotation of the disc 100). The clamping area 106 is defined by a ringwith an inner diameter of 22.0 mm and an outer radius of 33.0 mm.

The size/dimensions of the security tag 102 are generally bound by therequirement that it does not interfere with reading encoded data—andshould not be shielded by a metal layer, and therefore at least theantenna portion of the security tag 102 occupies non-readable regions ofthe secure disc 100. Thus, in embodiments of the invention, at least aportion of the security tag 102 extends beyond the clamping area 106 toother regions of the disc 100. For example, in an embodiment of theinvention the security tag extends into an annular portion 108 of thesecure disc 100 having an inner diameter of 15.0 mm and outer diameterof 22.0 mm. However, the tag 102 does not extend over the rim of thecenter hole (at a radial distance of 15.0 mm. from the rotational axisof the disc 100). In this embodiment the security tag 102 occupies anarea from 15.0 mm to 33.0 mm (just inside a stacking ring 110, ifpresent, at a diameter of 33.5 mm) thereby enhancing the signal strengthof the security tag.

Furthermore, to provide a stronger signal, in alternative embodiments ofthe invention, the outer edge of the surface area of the security tag102 is potentially extended into a non-readable region just beyond thestacking ring 110 diameter (33.5 mm). This region is referred to as the“mirror band” region of the disc. On the other hand, in such alternativeembodiments of the invention, the security tag 102 does not extendbeyond the mirror-band region into a readable region 112 of the securedisc 100 so as to obscure readable data tracks that begin at a diameterof 45.0 mm and end at a diameter of 118 mm in the illustrativeembodiment since the coil/antenna is not to be shielded by a metallayer. However, in embodiments of the invention, other circuitcomponents of the security tag 102, such as a capacitor or diode, arehidden under a metal layer, such as the mirror band, to fully utilizeavailable space to maximize the signal of the resonator.

The mirror band region contains information that is visually orelectronically scanned to provide information. In the case of a DVD withtwo content-laden substrates, two barcodes are provided. The barcodesare offset so that the reader can access both barcodes from one side ofthe disc. Due to the alignment of the stamper on the replicator, openspaces exist on the mirror band. In embodiments of the invention, theopen spaces are occupied by portions of the security tag 102 such as acapacitor. In such cases, the mirror band is isolated from the portionof the metal layer constituting the data portion of the disc throughdouble masking—i.e., a first mask is used to sputter the data tracks,and a second mask is used to sputter the mirror band. The secondsputtering stage deposits a thicker layer of metal for the mirrorthereby increasing its conductivity. The mirror band is thereafter usedas a portion of the antenna for the security tag 102.

As will be evident to those skilled in the art, the above-describedexemplary embodiment can be modified in a number of ways, including,without limitation modifying: any of the identified dimensions(including the disc itself), the size of the security tag 102, the typeof encoding of data on the disc (e.g., CD, DVD, etc.), the type ofinformation encoded/embodied in the security tag (e.g., an RFID tagproviding a value corresponding to the particular disc—as opposed tomerely resonating at a particular frequency to which a sensor is tuned),and the type of data on the data tracks of the disk (e.g., movies,games, application programs, music, etc.). Such modifications areintended to fall within the scope of the present invention.

Turning to FIGS. 2 a–d, partial cross-sectional views are provided offour exemplary types of secure DVD discs 200 a–d. These simplifiedcross-sectional views (corresponding to a side view of the secure disc100, when quartered) depict the general location of a security tag 202within the layers of exemplary secure disc structures. The security tag202, by way of example, comprises a polypropylene or polyethylene/Mylarbacking material imprinted with a metallic coil circuit. In anembodiment of the invention, the security tag 202 includes a capacitordevice that is short-circuited during deactivation (at the checkoutcounter). Suitable manufacturers of such tags are All-Tag Security S.A.Z.A.E. of Belgium and Checkpoint Systems, Inc. of Thoroughfare, N.J.

In an embodiment of the present invention, the security tag 202 isembedded within any of a variety of DVDs conforming to the followingdimensions. By way of example, each substrate is approximately 0.6 to0.5 mm. (but may be thinner to accommodate multiple readable layers on aside), and a bonding layer 204, used to hold the two substrates(including their reflective/transmissive data layers) is approximately0.10 mm. Therefore the total thickness of the DVD structure, regardlessof readable data layer format, is approximately 1.20 mm. (+0.30 mm/−0.06mm). The disc has an outer diameter of 120.00 mm (±0.30 mm), and thecenter hole has a diameter of 15.00 mm (+0.15 mm/−0.00 mm). The valuesin parentheses represent tolerances specified by the standard, ECMA-2673^(rd)Edition, April 2001, for 120 mm DVD read-only discs. Theabove-specified dimensions and tolerances are intended to be exemplaryand differ in alternative embodiments of the invention.

In an embodiment of the invention, the security tag 202 islocated/embedded within a space/layer of a secure disc referred toherein as the bonding/adhesive layer 204 having a thickness ofapproximately 0.10 mm. A suitable manufacturer of a bonding resin forthe bonding/adhesive layer 204 is Nagase California Corp. of Sunnyvale,Calif. The bonding/adhesive layer 204 is sandwiched between first andsecond polycarbonate substrates 208 x and 210 x of a secure DVD disc.Suitable polycarbonate material is provided by Teijin Kasei America ofAlpharetta, Ga. It is noted that in an embodiment of the invention, atag is placed within a molding cavity prior to the injection of thepolycarbonate. The polycarbonate flows over the tag and embeds the tagwithin the substrate half.

As demonstrated in the various embodiments of the secure disc depictedin FIGS. 2 a–c, the substrates are either “blank” or alternatively carryone or more metalized/reflective layers depending upon the disccapacity. It is noted that in illustrative embodiments of the inventionat least one of the substrates 208 x and 210 x is potentially “thinner”near the center hole. This accommodates a portion of the security tag202's thickness (approximately 0.02 mm) that exceeds the thickness ofthe bonding/adhesive layer 204 x. In embodiments of the invention, thetwo substrates are separately processed, and at a point just prior tobonding the two substrates 208 x and 210 x together, the security tag202 is placed upon one of the two substrates. Thereafter, the twosubstrates are bonded together using any appropriate bonding/adhesivematerial which forms the bonding/adhesive layer 204 x. It is noted thatthe views depicted in FIGS. 2 a–c are not to scale, but are intended toshow the general layers of various embodiments of a secure discembodying the present invention.

FIG. 2 a depicts a schematic cross-sectional view of a secure disc 200 areferred to as a DVD-5 along with suggested/exemplary dimensions—thatmay vary in accordance with various embodiments of the invention. TheDVD layers/format depicted in FIG. 2 a is used for DVD's that carry avariety of encoded data including, by way of example, movies and gameconsole-based video game software. The disc 200 a generally depictslayered structures specified for a single-sided, single readable layerDVD-5 disc. In the illustrative example the DVD-5 disc 200 a includes asingle reflective layer 206 a (approximately 10 microns thick) and isreadable on one side (as indicated by a laser beam 203 a). The securitytag 202 (approximately 0.1 mm. thick) is sandwiched, along with abonding/adhesive layer 204 a (approximately 0.07 mm.), between a blank(dummy) substrate 208 a (approximately 0.6 mm.) and a non-blanksubstrate 210 a (approximately 0.5 mm.) upon which the single reflectivelayer 206 a is deposited. It is specifically noted that the above layerthicknesses are provided for illustrative purposes and should not beconstrued as limiting the present invention. For example, modificationsto the tag 202 thickness potentially influence the thickness of thesubstrate and bonding resin layers. The reflective layer 206 a is, byway of example, aluminum. In embodiments of the invention the blanksubstrate 208 a optionally includes printed artwork on its outernon-readable surface 212. Finally, it is noted that in the illustrativeembodiments, the substrate 210 a thins beginning at point 213 of anon-readable portion adjacent to a center hole 215. The width differencein substrate 210 a (e.g., approximately 0.01 to 0.02 mm.) accommodates adifference in the thickness of the security tag 202 and thebonding/adhesive layer 204. While not specifically depicted in FIG. 2 a,the tag 202 is bonded to one, or both, of the substrates 208 a and 210 awith an adhesive (approximately 5 microns thick).

FIG. 2 b depicts a schematic cross-sectional view of a secure disc 200 bthat incorporates the layered structures specified for a single-sided,dual readable layer DVD-9 disc. In the illustrative example the DVD-9disc 200 b includes a reflective layer 206 b sputtered on a stampedsubstrate 208 b, and a semi-transmissive layer 207 b that is sputteredon a stamped substrate 210 b. The semi-transmissive layer 207 b is, byway of example, a very thin layer (e.g., 10 microns or less) of gold,silver, silver alloy or silicon. The security tag 202 occupies a layerof the DVD structure that is also occupied by a transparentbonding/adhesive layer 204 b between the stamped substrate 208 b whichcarries the reflective layer 206 b, and the semi-transmissive layer 207b sputtered upon the substrate 210 b. Methods for fabrication of the tworeadable layers on a single side of a DVD-9 disc are known to thoseskilled in the art. In exemplary embodiments of the invention, thereflective layer(s) are aluminum and the transmissive layer(s) are gold,silver, silver alloy, or silicon. The layer thicknesses for the DVD-9structure are generally the same as the ones described above for FIG. 2a.

FIG. 2 c depicts a schematic cross-sectional view of a secure disc 200 cthat incorporates the layered structures specified for a double-sided,dual readable layer DVD-18 disc. In the illustrative example the DVD-18disc 200 c includes on a first readable side: a reflective layer 206 c,a transparent bonding layer 209 c and a semi-transmissive layer 207 cfabricated on/attached to substrate 210 c. The second readable sideincludes: a reflective layer 216 c, a transparent bonding layer 219 cand a semi-transmissive layer 217 c fabricated on/attached to substrate208 c. While not specifically depicted in FIG. 2 c, protective layers(see FIG. 6 a and FIG. 6 b) are spin coated on their respective halvesof the disc 200 c to protect the reflective metal layers. Thereafter,the secure tag 202 is placed upon one of the two halves of the DVD-18corresponding to substrates 208 c and 210 c. Finally, the two halves arebrought together to form a layered structure wherein the security tag202 occupies a layer of the DVD structure that is also occupied by thebonding/adhesive layer 204 c between the protective layers. In yetanother embodiment, the security tag 202 is placed between substratehalves of a dual-readable side DVD-14 structure. It is noted that, inthe illustrative embodiment, the thickness of the metal and bondinglayers are sufficiently thick in the DVD-18 structure such that a changein substrate thickness is not needed at point 213. In other embodimentsthe thickness of one or more of the two substrates is thinned at aportion where the tag is placed to accommodate the tag thickness.

Turning briefly to FIGS. 3 a–d, a set of exemplaryconfigurations/geometries for the security tag are provided. Asexplained previously above, the security tag fits, by way of example,within the clamping area of a DVD or other optically readable datastorage disc. The coils of the security tag can take any of a number ofshapes and sizes—subject to the space limitations imposed by the discgeometry. FIGS. 3 a, 3 b and 3 c schematically depict embodiments ofminiature coil configurations. In these embodiments signal strength isenhanced by creating multiple replicated coil pairs and distributing thecoils around the perimeter of a ring substrate for the security tag 202.FIG. 3 d, on the other hand, derives signal strength through the use oflarge ring-shaped coils that conform to the ring-shape of the securitytag 202's substrate. Alternative embodiments of the invention utilizeother shapes/coil layouts.

Having described exemplary structural features of exemplary DVDstructures embodying the present invention, attention is directed to themethods for fabricating such structures. Referring to the sequence ofFIGS. 4 a–b, 5 a–b and 6 a–b, the process for manufacturing DVD-14 andDVD-18 disc structures is summarized by way of identifying the layers ateach of three primary stages. It is noted initially that a DVD-14 istwo-readable-side DVD having a DVD-9 readable side and a DVD-5 readableside bonded together. A DVD-18 has two DVD-9 readable sides bondedtogether. The overall thickness of the DVD discs conforms to the 1.20 mmthickness specification.

Generally, in order to maintain the overall thickness specification of1.20 mm. for a DVD, substrates used to fabricate the multiple readablelayers are stripped and discarded so that the combined thickness isstill 1.20 mm. To facilitate such stripping, an acrylic blank (that willrelease the aluminum without damaging the reflective layer) is used asthe substrate for the reflective layer. The process starts with themanufacturing of a DVD 9 and a DVD 5 combination for DVD-14 or twoDVD-9's for DVD-18. The information for the three readable layers forDVD-14 originates from three different stampers. Four stampers are usedto produce the readable layers for DVD-18.

FIGS. 4 a and 4 b illustratively depict the initial molding/bondingprocesses. When a DVD-14 is manufactured, the half disc for the DVD-5portion is molded. However, as shown in FIG. 4 b, it is not necessary tobond a blank substrate to the DVD-5 disc because it will eventually bebonded to the DVD-9 substrate. The DVD-9 substrates are manufactured inthe nearly same way as standard DVD-9's. However, the DVD-9 portion ofthe sandwich includes an acrylic layer for layer 1 instead of thestandard polycarbonate used for DVD-9. Acrylic is used for the layer 1substrate because it adheres poorly to aluminum.

The acrylic layer, which has the information molded into its surfacefrom a stamper, can be pealed off the substrate during a strippingprocess, leaving the information embossed in the cured bonding lacquerlayer with an aluminum surface. In principle, the acrylic substrate actslike a stamper as it is used to transfer the image of the pits into thecured bonding resin. The stripping process results in the layeredstructures described in FIGS. 5 a and 5 b. After the two DVD-9's in thecase of DVD-18 are made or a DVD-9 and DVD-5 are made in the case of DVD14, the DVD 9 portions go to the stripping process. The strippingprocess peals the acrylic substrates off the surface.

After stripping, the two disc halves are bonded together to yield atwo-sided disc with four layers (two per side) for DVD-18 or a two-sideddisc with three layers—two on one side and a single layer on theother—for DVD-14. A first step before the second bonding processcomprises spin coating the exposed aluminum sides of the previouslystripped disc halves with a CD-type UV protective coating. After thehalves are protective coated (two DVD-9 disc halves for DVD-18 or oneDVD-5 half and one DVD-9 half for DVD-14) the disc halves are bondedtogether. In accordance with an exemplary embodiment of the invention,the security tag 202 is applied to one of the two disc halves eitherduring molding of a substrate or alternatively after sputtering andprior to re-bonding. In a particular illustrative embodiment, while anindexing carousel transfers a disc half containing the reflective metallayer to the final bonding stage, rotation of the table is temporarilypaused and an applicator attaches (e.g., dispenses and tamps in place)the security tag 202 to the disc half prior to the application of thebonding resin and the final combination of the disc by a consolidatormachine. After the bonding step a clamping mechanism ensures that thetwo substrates are securely attached to the tag and that the securitytag 202 does not compromise the structural integrity of the secure disc200.

Once the disc halves are bonded together the security tag 202 cannot beremoved, yet the disc maintains all of the structural integrity ofnon-secure discs that do not include the security tag 202 embeddedbetween the two substrates. FIGS. 6 a and 6 b provide the finalconfiguration for the DVD-18 and DVD-14 formats. The security tag 202 iscontained in the second bonding layer.

Turning to FIG. 7 a portion of a DVD assembly line is depicted. Theillustrative set of machines manufactures either DVD-5 or DVD-9(depending upon whether both sides are stamped/sputtered). Eachsubstrate is initially produced by a molding/stamping sub-assembly 700or 702 by Meiki Molding of Nagoya, Japan. Transfer arms 704 and 706transfer the substrates to sputtering machines 708 and 710 made byUNAXIS of Luxembourg, if the substrate is a non-blank substrate. Thesputtered or blank substrate is transferred by the transfer arms 704 and706 to an indexing carousel 712. In an embodiment of the invention,while the substrate is laying, inside face up, on the indexing carousel712 at position 714 (before applying a bonding resin and consolidatingthe two halves to form a single DVD, a tag applicator applies thesecurity tag 202 to one of the two halves. Thereafter, the DVD halvesare transferred by a transfer arm 716 to a consolidating assembly 718. Aflipper 720 flips one of the two disc halves in preparation forconsolidation while an applicator 722 applies bonding resin to the otherhalf. Thereafter, a consolidator 724 mates the two halves of the disc torender a DVD-5 or DVD-9 disc. Thereafter, a spinner spins excess bondingresin from the consolidated disc assembly and the resin is cured throughexposure to a UV light source. Inspection and printing stages completethe exemplary DVD assembly processes. The robotic transfer arms,indexing carousel 712 and components of the consolidating assembly 718are provided, for example, by Origin of Tokyo, Japan.

Turning to FIGS. 8 a and 8 b, a set of schematic flow diagramsillustratively depict the primary stages for creating replicated DVD-5and DVD-9 discs, respectively. These FIGS. schematically depict twoalternative sequences of operations performed by the manufacturing linedepicted in FIG. 7. With reference to FIG. 8 a, a stamper line generatesan embossed substrate at stage 800. Thereafter, the reflective(aluminum) coating is applied (sputtered) at stage 802 to render thedata bearing half of the disc. At stage 804, while the disc halfcontaining the reflective metal layer is being transferred to a bondingstage 806, wherein the data half is mated with a blank substrateprovided by molding stage 807, the security tag 202 is applied to the“reflective” half. It is noted that in alternative embodiments of theinvention, the security tag 202 is initially applied to the blank halfafter molding stage 807. It is further noted that in yet otherembodiments, the tag 202 is embedded within either of the two substratehalves during either of the two injection molding stages 800 and 807.After the bonding stage 806, described in greater detail above withreference to FIG. 7, the disc is inspected at stage 808. Thereafter,printing is placed upon the blank side of the DVD during stage 810.

With reference to FIG. 8 b, a stamper line generates an embossedsubstrate at stage 820. Thereafter, the reflective (aluminum) coating isapplied (sputtered) at stage 822 to render one data bearing half of theDVD-9 disc. At stage 824, while the disc half containing the reflectivemetal layer is being transferred to a bonding stage 826, wherein thedata half containing the reflective metal (Al) layer is mated with asecond data half containing a semi-transmissive metal (Ag or Au) layerprovided by stamper stage 827 and semi-transmissive layer stage 829, thesecurity tag 202 is applied to the “reflective” half. It is noted thatin alternative embodiments of the invention, the security tag 202 isinitially applied to the “semi-transmissive” half after thesemi-transmissive layer stage 829. However, for timing purposes, in anembodiment of the invention wherein one of the two sputtering processestakes longer than the other (e.g., the semi-transmissive layer takeslonger to produce than the reflective layer), the security tag isapplied to the half that takes less time to coat with a metal layer. Itis further noted that in yet other embodiments, the tag 202 is embeddedwithin either of the two substrate halves during either of the twoinjection molding stages 820 and 827. After the bonding stage 826,described in greater detail above with reference to FIG. 7, the DVD-9disc is inspected at stage 828. Thereafter, printing is placed upon theblank, non-readable side of the DVD-9 disc during stage 830.

In view of the many possible embodiments to which the principles of thisinvention may be applied, it should be recognized that the embodimentsdescribed herein with respect to the drawing figures are meant to beillustrative only and should not be taken as limiting the scope ofinvention. Furthermore, the illustrative steps may be modified,supplemented and/or reordered (at least in part) without deviating fromthe invention. Therefore, the invention as described herein contemplatesall such embodiments as may come within the scope of the followingclaims and equivalents thereof.

1. A secure optical data storage disc comprising: a first substrate; asecond substrate; and a non-readable zone comprising a security tag,wherein at least one of the first and second substrates has anon-uniform thickness to facilitate accommodating a thickness of thesecurity tag that exceeds a bonding layer between the first and secondsubstrates, and wherein the thickness of the security tag exceeds adepth of a depression in one of the first and second substrates createdby the non-uniform thickness such that at least a portion of thesecurity tag falls within a plane comprising the bonding layer.
 2. Thesecure disc of claim 1 wherein the security tag comprises a metal coil.3. The secure disc of claim 2 wherein the metal coil is laid out as aset of rings.
 4. The secure disc of claim 3 wherein the set of rings areconcentric.
 5. The secure disc of claim 2 wherein the metal coil is laidout as a set of non-concentric coils.
 6. The secure disc of claim 2wherein the metal coil comprises a set of non-circular coils.
 7. Thesecure disc of claim 6 wherein the set of non-circular coils arenon-concentric.
 8. The secure disc of claim 2 wherein the security tagcomprises a thin-film insulator sandwiched between metal coil pairs. 9.The secure disc of claim 1 wherein the secure disc comprises aninformation layer sandwiched between the first and second substrate, andwherein the security tag is also sandwiched between the first and secondsubstrate.
 10. The secure disc of claim 1 wherein the non-readable zoneis substantially located within a clamping zone.
 11. The secure disc ofclaim 1 wherein the non-readable zone extends into a mirror band region.12. The secure disc of claim 1 wherein data carried on the disccomprises videogame console software.
 13. The secure disc of claim 1wherein data carried on the disc comprises a movie.
 14. The secure discof claim 1 wherein the security tag incorporates radio frequencyidentification technology.
 15. The secure disc of claim 1 wherein thedisc conforms to a DVD standard specification.
 16. The secure disc ofclaim 1 wherein the secure disc comprises multiple data layers readablefrom a single side.
 17. The secure disc of claim 1 wherein the securedisc comprises dual readable sides.
 18. A method for manufacturing asecure optical data storage disc comprising a first substrate, a secondsubstrate, and a non-readable zone that is not occupied by data tracks,the method comprising: forming the first substrate and the secondsubstrate; securing a security tag to one of the first or secondsubstrates within the non-readable zone; and bonding the first substrateand second substrate together such that the security tag is positionedbetween the first and second substrates, wherein the forming stepcomprises forming at least one of the first and second substrates with anon-uniform thickness to accommodate at least a portion of a thicknessof the security tag, and wherein the thickness of the security tagexceeds a depth of a depression in one of the first and secondsubstrates created by the non-uniform thickness such that at least aportion of the security tag falls within a plane comprising the bondinglayer.
 19. The method of claim 18 wherein the forming and securing stepsare performed during an injection molding stage wherein the security tagis placed within an injection mold for forming one of the first andsecond substrates prior to injecting a molten substrate material. 20.The method of claim 18 further comprising the steps of: applying areflective layer to the first substrate, and, before the bonding step,placing the security tag upon the first substrate during the securingstep.
 21. The method of claim 18 wherein the secure disc comprisesmultiple data layers readable from a single side.
 22. The method ofclaim 18 wherein the secure disc comprises dual readable sides.
 23. Themethod of claim 18 wherein the depression extends to an inner hub of theone of the first and second substrates.
 24. The secure disc of claim 1wherein the depression extends to an inner hub of the one of the firstand second substrates.